refactor: modernize code quality tooling with Ruff

- Replace black, isort, and flake8 with Ruff (all-in-one linter and formatter)
- Add comprehensive pyproject.toml configuration
- Simplify Makefile code quality targets
- Configure exclusions for venv/.venv in pyproject.toml
- Auto-fix 1,359 linting issues across codebase

Benefits:
- Much faster builds (Ruff is written in Rust)
- Single tool replaces multiple tools
- More comprehensive rule set (UP, B, C4, SIM, PIE, RET, Q)
- All configuration centralized in pyproject.toml
- Better import sorting and formatting consistency

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

middleware/context.py

@@ -70,7 +70,7 @@ class ContextManager:
             host = host.split(":")[0]
 
         logger.debug(
-            f"[CONTEXT] Detecting context",
+            "[CONTEXT] Detecting context",
             extra={
                 "original_path": request.url.path,
                 "clean_path": getattr(request.state, "clean_path", "NOT SET"),